Real time plot simulink

Hi guys, i'm trying to do a polar plot with a matlab function in simulink that sould be tracked in real time during the simulation, but it doesn't work. Do you have any suggestions?

Answer 1

[Sahas]

Hi @ANGELO MASSARA,

As per my understanding, you want guidance to plot a “polarplot” function that can be tracked in real-time using a “MATLAB function block” inside Simulink. One possible solution is to use the “polarplot” function in MATLAB.

I have provided an example file “sample_polarplot_realtime_final.slx.” Execute this file and see plotting of the “polar axes” in real time.

Please refer to the following description for further understanding of the attached Simulink file:

The Simulink Model has two input blocks. “theta” is input for angle values and “rho” for the radius. I have provided such inputs to plot a circle.

The “updatePolarPlot” MATLAB Function Block contains the logic behind plotting the figure in real time.

function updatePolarPlot(theta, rho)
    %persistent figure and axes to maintain the plot between function calls
    persistent h ax; 
    
    % Check if the figure and axes are empty and initialize them if they are
    if isempty(h) || isempty(ax)
        h = figure;
        ax = polaraxes(h);
    end
    
    n = numel(theta); %Getting thenumber of elements in theta or rho
    for i = 1:n
        % Update the polar plot with the current subset of theta and rho 
        % values iteratively
        polarplot(ax, theta(1:i), rho(1:i));

        title('Real-Time Polar Plot');

        % Update the plot immediately
        drawnow;
    end
end

After executing, you will be able to see the figure plotting a complete circle in real time.

For further readings about the various functions and tools I have used, refer to the links below:

Plot line in polar coordinates - MATLAB polarplot - MathWorks India – Basics of the “polarplot” function in MATLAB.

I hope this helps you get started!